Desiccating food



UNITED STATES PATENT OFFICE.

JOHN F. KELLY, OF PITTSFIELD, MASSACHUSETTS.

DESICGA'IING FOOD.

1,393,540. No Drawing.

To all whom it may concern:

Be it known that I, J OHN F. KELLY, a citizen of the United States, residing at Plttsfield, in the county of Berkshire and State of Massachusetts, have invented certain new and useful Improvements in Desiccatmg Foods, of which the following is a speclfication.

This invention relates to desiccating foods; and it comprises a methodof desiccating fruits, vegetables, etc., wherein the material prior to the desiccation proper is moretened or treated with a solution contalnlng reducing sugars and is thereafter deslccated; all as more fully hereinafter set forth and as claimed.

Fruits and vegetables of course contain very many constituents and in part these substances are sensitive to the action of alr. As long as a fruit, such as an apple, 1s lntact air does not readily gain access to the tlssues or affect them but as Soon as the skin is broken air begins to act and discoloration is usually produced. The action of iron from cutting tools facilitates and accelerates this 11153- coloration but is not necessary to it. The same discoloring action by the action of air, though in less degree, occurs with very many other raw vegetable products such as potatoes. A potato if sliced and then drledi 1n the raw state is apt to discolor more or less, giving a dark product. On rehydratlng by treating with water a material is obtained which is different in color and appearance from the original potato and on cooking does not give a cooked product like that made from raw potatoes. It is usually believed that this discoloring action of the air on vegetable constituents is, at least in part, due to the presence of what are known as enzyme; unorganized vegetable ferments. All vegetable tissues contain these enzyme and in part they are oxygen transferring or oxidizing enzyms or laccases. They are readily destroyed by a high heat. If, for example, a potato be boiled or parboiled prior to slicing and drying, it does not darken up in drying in the manner described; but in so operating desiccated raw potato cannot of course be made. The dried material is dried cooked potato and it cannot be recooked like raw potato.

It has been found that discoloration may be prevented in other ways than by cooking, as for instance by the use of various chemicals which poison the enzyme and prevent 1 its action.

Specification of Letters Patent. P t t Oct 11 1921,

Application filed August 4, 1919. Serial No. 315,297.

their exerting their normal activity. But the use of these chemical materials in edible products is of course inadmissible or undesirable. L

l have found that I can accomplish the desired end in another manner which consists in providing a very small amount of reducing sugar on the-surfaces of the fruit or vegetable during the drying operation. The sugars are of course edible materials and their presence in no way harms the food. In the presence of a reducing sugar the activity of the oxidizing enzym appears to be diverted from the natural constituents of the fruit or vegetable which will discolor under Perhaps the action is then the oxidation of the reducing sugar; this oxidation not being attended with the production of dark products. At all events, in the presence of a reducing sugar'the discoloration of the raw fruit or vegetable which normally takes place in drying does not occur.

In practical embodiments of my invention I immerse the cut or sliced fruit or vegetable in a. dilute solution of a reducing sugar or of material containing the same. Ordinary glucose or corn sugar solutions will serve. A better preparation is made by mixing cane or beet sugar, such as ordinary loaf sugar, with a little acid. The action of the acid is to convert or invert the sucrose into reducing sugars (dextrose and levulose) and the amount of acid required for this purpose is so infinitesimal as to be-unimportant. I find it a useful expedient to employ a little alcohol in maln'ng the solution-of reducing sugars to be used as it then wets and spreads better on the out surfaces of the fruit or vegetable. A good composition for the present purposes may be made by taking a 10 per cent. solution of cane sugarand adding a little alcohol and any convenient acid to it. 1 or 2 parts of citric acjd to 200 parts of water, 20 parts of loaf sugar and 20 parts of alcohol make a good stock solution which can be further diluted; say to a solution containing 0.10 er cent. sugar. When using citric acid which does not have a strong inverting or convert ing action on sugar in the cold, the stock solution is best boiled for a time. By using stronger acids such as nitric or hydrochloric acid the action on the sugar, or what is termed inversion can be accomplished in the cold. Using hydrochloric acid it may be simply added to'the solution in the cold reducing sugars.

and the solution allowed to stand a few hours, sa 3 or 4' hours. A little bicarbonate of so a can be added to convert the acid into ordinary salt.

In drying potatoes the raw potato may be sliced or cut in any of the ordinary ways and then dipped into the solution, drained and dried in any of the usual ways and with any' of the usual apparatus.- The amount of sugar required to accomplish my purpose is almost infinitesimal being no more than about a tenth 'or hundredth part for 100 arts of raw potato. The same solution may be used for apples, carrots, turnips, etc., and in the same-way.

Other reducing materials normally found in food products may be substituted for these sugars, as for instance, cream of 'tar-' tar, but they olfer no special advantage over I find however that reducing vegetable acid materials like citric 'acid, tartaric acid, cream of tartar, (acid potassium tartrate,) etc., are excellent additions to solutions of reducing sugars.

Used alone their action is probably that of forming reducing sugars in small amounts from various carbohydrate components of the cut vegetable surfaces such as starch.

What I claim is P 1. In the desiccation of raw succulent vegetable and fruit products the process which comprises applying a solution contaming ,a reducing sugar to cut surfaces and thereafter desiccating in the usual way.

2. In the desiccation of raw succulent vegetable and fruit roducts, the process wh ch comprises app ying a solution containing a reducing sugar and also containing a vegetable acid material of reducing nature to cutsurfaces and thereafter desiceating 1n the usual way.

In testimony whereof, I aflix my signature hereto.

. JOHN KELLY.

V Witnesses: I i

JOHN. EAGHAN KELLY, 'S. A. ODANmL. 

